Added TestNG extension

- added testNG extension ESServerExtension to wait test execution untill jaggery apps get deployed/populated properly
- updated test cases

This file has been renamed in a later pull request and ==== has been removed.

https://github.com/ayshsandu/enterprise-store/blob/ui-test/modules/integration/tests-common/integration-test-utils/src/main/java/org/wso2/es/integration/common/utils/ESServerExtension.java